As someone who has been throwing around the same article
as Lisp advocacy, I felt compelled to put in my say. :-) I do
basically agree with Tilly's points. I guess I feel there
are (at least) two distinct kinds of language advocates:
those who rabidly and unconditionally push their own favorite
language(s), and those (among whom I like to fancy myself)
simply want to make sure that someone has a reasonable
understanding of a tool before dismissing it for a task.
I have to admit that I get very tired of hearing rampant
misconceptions about Lisp (or Perl, or Smalltalk, etc.) -
it's slow, it's interpreted, it's only good for AI, etc.,
and I find that it's puzzling that people are willing to
propagate such without bothering to check out for themselves
whether or not they are true, and Graham's piece is at
least a good pointer to get people to reconsider their
preconceptions, and perhaps look into things more deeply.

One of Graham's point that I found particularly
interesting is that people are often
loathe even to consider the possibility that tools other than
the ones they are accustomed to may sometimes be able to
bring more power to bear on problems, while at the same time
they are willing to look down on tools that are demonstrably
less powerful for the same problems. I wonder how
it is that we can become so indoctrinated in certain ways of
thinking and working (and I do not always exclude myself here)
that we miss the opportunity to discover new and better ways
to do things? I find that such experimentation is one of the
enjoyable things about this field.